U.S. patent number 4,725,208 [Application Number 06/837,840] was granted by the patent office on 1988-02-16 for positive shut off electromagnetic fluid pump.
This patent grant is currently assigned to Facet Enterprises, Inc.. Invention is credited to Ralph V. Brown.
United States Patent |
4,725,208 |
Brown |
February 16, 1988 |
Positive shut off electromagnetic fluid pump
Abstract
A positive shut-off electromagnetic fluid pump of the type
having a piston electromagnetically reciprocated in a cylindrical
guide by a solenoid coil and a pair of valves for providing a
unidirectional fluid flow from an inlet port to an outlet port in
response to the reciprocation of the piston. An elastomer bumper
attached to the piston occludes the outlet port when the piston is
biased to its extreme position adjacent to the outlet port when the
solenoid coil is de-energized.
Inventors: |
Brown; Ralph V. (Cayuta,
NY) |
Assignee: |
Facet Enterprises, Inc. (Tulsa,
OK)
|
Family
ID: |
25275589 |
Appl.
No.: |
06/837,840 |
Filed: |
March 10, 1986 |
Current U.S.
Class: |
417/417;
310/30 |
Current CPC
Class: |
F04B
17/046 (20130101) |
Current International
Class: |
F04B
17/04 (20060101); F04B 17/03 (20060101); F04B
017/04 () |
Field of
Search: |
;417/415,417,418 ;92/85R
;310/30 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Croyle; Carlton R.
Assistant Examiner: Thorpe; Timothy S.
Attorney, Agent or Firm: Ignatowski; James R. VanOphem; Remy
J.
Claims
What is claimed is:
1. A positive shut-off electromagnetic fluid pump comprising:
a housing having a cylindrical passageway, an inlet port disposed
at one end of said cylindrical passageway, and an outlet port
disposed at the other end of said cylindrical passageway;
a hollow cylindrical piston slidably disposed in said cylindrical
passageway;
resilient means for biasing said piston towards said outlet
port;
a solenoid coil for generating a magnetic force to displace said
piston towards said inlet port against the force of said resilient
means;
electronic circuit means for periodically energizing said solenoid
coil to cause said piston to reciprocate in said cylindrical
passageway;
valve means for providing a unidirectional fluid flow through said
cylindrical passageway from said inlet port to said outlet port in
response to the reciprocation of said piston; and
elastic bumper means attached to the end of said piston adjacent to
said outlet port for inhibiting a fluid flow through said outlet
port when said piston is displaced to its extreme position adjacent
to said outlet port by said resilient means.
2. The fluid pump of claim 1 wherein said outlet port is concentric
with said cylindrical passageway and said elastic bumper means is
concentric with said outlet port.
3. The fluid pump of claim 2 having an aperture plate disposed at
the end of said cylindrical passageway adjacent to said outlet
port, said aperture plate having a centrally disposed aperture
connecting said cylindrical passageway with said outlet port and
wherein said aperture is occluded by said elastic bumper means.
4. The fluid pump of claim 3 wherein said elastic bumper means
comprises a support plate attached to the end of said piston and an
elastomer bumper attached to said support plate concentric with
said aperture.
5. The fluid pump of claim 4 wherein said elastomer bumper is made
from an elastomer compounded for minimum swelling in non-leaded
gasoline.
6. The fluid pump of claim 1 wherein said electronic circuit means
is a blocking oscillator.
7. A positive shut-off electromagnetic pump having a housing
defining an internal cylindrical passageway, an inlet port provided
at one end of said internal cylindrical passageway, an outlet port
provided at the other end of said internal cylindrical passageway,
a piston disposed in said internal cylindrical passageway between
said inlet and outlet ports, resilient means for biasing said
piston towards said outlet port, a solenoid coil for generating a
magnetic force to displace said piston towards said inlet port
against the bias of said resilient means, electronic means
periodically energizing said solenoid coil to reciprocate said
piston in said internal cylindrical passageway, and valve means for
providing a unidirectional fluid flow through said pump in response
to the reciprocation of said piston, said positive shut-off fluid
pump characterized by an elastic bumper attached to the end of said
piston for occluding said outlet port to prevent a fluid flow
therethrough in either direction when said piston is displaced by
said resilient means to its extreme position adjacent to said
outlet port when the solenoid coil is de-energized.
8. The pump of claim 7 wherein said housing includes an aperture
plate disposed at the end of said internal cylindrical passageway
adjacent to said outlet port, said aperture plate having an axially
disposed aperture providing a fluid connection between said
internal cylindrical passageway and said outlet port, and wherein
said aperture is occluded by said elastic bumper to prohibit a
fluid flow through said outlet port when said piston is displaced
to its extreme position by said resilient means.
9. The pump of claim 7 wherein said elastic bumper comprises:
a support plate attached to the end of said piston adjacent to said
outlet port; and
an elastomer bumper attached to said support plate concentric with
said outlet port.
10. The pump of claim 9 wherein said support plate has an axial
aperture provided therethrough, and said elastomer bumper has an
enlarged head disposed on the surface of said support plate
adjacent to said outlet port, a stem received through said axial
aperture and a button provided at the end of said stem engaging the
other surface of said support plate to secure said elastomer bumper
to said support plate.
11. The pump of claim 9 wherein said elastomer bumper is made from
an elastomer compounded to have minimum swelling in unleaded
gasoline.
12. A positive shut-off reciprocating piston fluid pump
comprising:
a cylindrical guide;
an inlet port disposed at one end of said cylindrical guide;
an outlet port disposed at the other end of said cylindrical
guide;
a hollow cylindrical piston disposed for reciprocation in said
cylindrical guide;
a spring biasing said piston towards said outlet port;
electromagnetic means cooperating with said spring for
reciprocating said piston in said cylindrical guide;
valve means responsive to the reciprocation of said piston for
providing a unidirectional fluid flow through said cylindrical
guide; and
an elastomer bumper attached to the end of said piston for
occluding said outlet port when said electromagnetic means is
de-energized and said piston is displaced to its extreme position
adjacent to said outlet port by said spring.
13. The fluid pump of claim 12 wherein said outlet port and said
elastomer bumper are disposed concentric with the axis of said
cylindrical guide.
14. The fluid pump of claim 13 wherein said outlet port includes an
aperture plate having an exit aperture occluded by said elastomer
bumper when said piston is displaced to its extreme position
adjacent to said outlet port by said spring.
15. The fluid pump of claim 12 wherein said electromagnetic means
comprises:
a solenoid coil circumscribing said cylindrical guide; and
an electronic circuit for periodically energizing said solenoid
coil.
Description
FIELD OF THE INVENTION
The invention is related to electromagnetic fluid pumps and, in
particular, to a positive shut off mechanism to eliminate fluid
siphoning and/or draining when the power to the pump is turned
off.
BACKGROUND OF THE INVENTION
Electromagnetic fluid pumps of the type taught by Wertheimer in
U.S. Pat. No. 3,400,663 or by Brown in U.S. Pat. No. 4,079,436 have
found wide acceptance for a variety of uses in both the industrial
and commercial markets. One of the problems encountered in the use
of these pumps is that they have a tendency to drain and loose
their prime when they are located above the fluid reservoir or to
siphon fluid from the fluid reservoir when they are located below
the level of the fluid reservoir. This problem has been addressed
by the prior art in a variety of ways. Barthalon in U.S. Pat. No.
4,021,151 discloses a reciprocating piston air pump in which the
outlet ports are disposed in the side walls of the compression
chamber. In the unactuated state of the pump the piston is biased
to a full upward position in which the side walls of the piston
block the outlet passages. Toyoda in U.S. Pat. No. 4,252,505
discloses a reciprocating piston fluid pump having a separate
spring biased valve member to block the pump's outlet port when the
pump is de-energized. The separate valve member is displaced to the
open position by a separate solenoid coil. Nakamura in U.S. Pat.
No. 3,877,841 and Nomura in U.S. Pat. No. 4,255,094, like Toyoda,
disclose a separately movable valve member to block or shut off the
pump's outlet port when the pump is de-energized. This movable
valve is open only when the solenoid coil is energized. The present
invention is a solution to the siphoning and draining problems
which eliminates the need for a separate movable valve to close the
outlet port when the solenoid coil is de- energized.
SUMMARY OF THE INVENTION
The present invention is a positive shut-off electromagnetic fluid
pump having a housing defining a cylindrical guide, an inlet port
disposed at one end of the cylindrical guide and an outlet port
disposed at the other end. The pump further has a spring which
biases the piston towards the outlet port, a solenoid coil for
displacing the piston towards the inlet port, an electronic circuit
for periodically energizing the solenoid to reciprocate the piston
in the cylindrical guide, a pair of valves for providing
unidirectional fluid flow from the inlet port to the outlet port in
response to the reciprocation of the piston, and an elastic bumper
attached to the end of the piston adjacent to the outlet port for
occluding the outlet port when the piston is biased by the spring
to its extreme position adjacent to the outlet port.
The principal object of the present invention is to provide a
positive shut-off of the fluid flow through the pump when the pump
is de-energized. Another object of the invention is to prohibit
siphoning through the pump when the utilization device is disposed
at a lower level than the fluid in the reservoir. A final object of
the invention is to provide a positive shut-off of the fluid flow
through the pump without the need for an independent movable valve
member and/or external solenoid valves.
These and other objects of the present invention will become more
apparent from a reading of the specification in conjunction with
the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional side view of the positive shut-off
electromagnetic fluid pump;
FIG. 2 is a top view of the non-magnetic bumper bracket; and
FIG. 3 is a side view of the elastic bumper.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown an electromagnetic fluid pump
10 having positive shut-off capabilities. The pump 10 has a
cylindrically shaped piston 12 slidably disposed in a non-magnetic
cylindrical guide member 14. One end of the cylindrical guide
member 14 is attached to an outlet housing member 16 having a fluid
outlet port 18 provided therethrough concentric with the guide
member 14. The other end of the guide member 14 is attached to an
inlet housing member 20 having a fluid inlet port 22 provided
therethrough concentric with the guide member 14.
A first valve member 24 is attached to the piston 12 at the end
adjacent to the fluid inlet port 22 and a second valve member 26 is
attached to the inlet housing member 20 and controls the fluid flow
through the fluid inlet port 22. The first and second valve members
24 and 26, respectively, operate in a known manner to provide a
unidirectional fluid flow through the pump 10 from the inlet port
22 to the outlet port 18, as indicated by arrow 25.
A piston spring 28 disposed in the guide member 14 between the
piston 12 and a spring seat member 30 produces a force biasing the
piston 12 towards the outlet port 18 and the spring seat member 30
towards the inlet port 22. A valve spring 32 disposed between the
spring seat member 30 and the second valve member 26 biases the
second valve member to close or occlude the inlet port 22.
A solenoid coil 34 circumscribes the guide member 14 and produces a
magnetic force operative to displace the piston 12 towards the
inlet port 22 against the force of the piston spring 28. The
solenoid coil 34 is energized by an electronic circuit 38. The
electronic circuit 38 may be a blocking oscillator of the type
taught by R. V. Brown in U.S. Pat. No. 4,464,613 responsive to the
signal induced in a detector coil 36 or may be any other type of
electronic oscillator or timer circuit operative to periodically
energize the solenoid coil 34 causing the piston 12 to reciprocate
within the guide member 14.
Attached to the end of the piston 12 adjacent to the outlet port 18
is a support plate 40 having a centrally disposed aperture 42. The
support plate 40 has a spider like configuration, as shown in FIG.
2, to permit a fluid flow therepast. Preferably the support plate
is made from a plastic or non-magnetic material but may be made
from a magnetic material. The support plate 40 may be pressed into
a recess 44 provided at the end of the piston 12 or attached to the
end of the piston 12 using any other method known in the art. An
elastic bumper 46, having the configuration shown in FIG. 3, is
pressed into the aperture 42 provided in the support plate 40. A
button 52 provided at the end of a button stem 54 locks the elastic
bumper 46 in the support plate's aperture. The elastic bumper 46
has an enlarged head 56 which occludes an aperture 50 provided in
an outlet aperture plate 48. Alternatively, the elastic bumper 46
may consist of only the enlarged head 56 which is bonded to the
surface of the support plate 40.
The aperture plate 48 is captivated between the end of the guide
member 14 and the outlet housing member 16 with the aperture 50
concentric with the elastic bumper 46. In an alternate embodiment,
not shown, the aperture plate may be eliminated and the diameter of
the outlet port 18 reduced to a size smaller than the diameter of
the elastic bumper's enlarged head 56.
The elastic bumper 46 is preferably made from an elastomer, such as
BUNA-N or VITRON, compounded for low swelling in unleaded
gasoline.
The inlet and outlet ports 22 and 18, respectively, may be
threaded, as shown in FIG. 1, to facilitate the attachment of
connecting fluid pipes, hoses, etc. as is known in the art.
In the static or de-energized state of the positive shut-off fluid
pump the piston spring 28 biases the piston 12 towards the outlet
port 18. In the extreme displaced position of the piston 12 the
elastic bumper 46 seals or occludes the aperture 50 of the aperture
plate 48 which prevents a fluid flow in either direction through
the outlet port 18. Therefore, in the static or unenergized state,
fluid can neither be siphoned from nor be drained back into the
fluid reservoir, through the pump 10. Further, there is no
hydraulic lockup of the pump because the bumper 46 will only seal
the aperture 50 when the piston is fully displaced by the piston
spring 28 towards the outlet port 18. From this position, the
piston 12 can only be displaced away from the outlet port 18 by the
solenoid coil 34. The displacement of the piston 12 away from the
outlet port does not change the internal volume of the pump defined
by the guide member 14 and the outlet and inlet housing members 16
and 20, respectively. As the piston 12 is displaced towards the
inlet port 22 by the solenoid coil 34, the first valve member 24
will open permitting the piston to move freely. Once the piston is
displaced the outlet port is opened. Thereafter the piston 12 is
free to reciprocate in response to the electronic circuit
cyclically energizing the solenoid coil 34. Reciprocation of the
piston 12 will provide a unidirectional fluid flow through the pump
from the inlet to the outlet ports. As previously described, the
direction of the fluid flow is determined by the first and second
valve members 24 and 26, respectively. When the pump is
de-energized the piston spring 28 will again displace the piston 12
to its extreme position adjacent to the outlet port 18 with the
elastic bumper 46 sealing the exit aperture 50.
It is not intended that the invention be limited to the specific
embodiment illustrated in the drawings and discussed in the
specification. It is recognized that a person skilled in the art
will be able to adopt the invention to other pump configurations or
make changes within the spirit of the invention as described above
and set forth in the appended claims.
* * * * *